UML Model Refactoring Viktor Stojkovski University of Antwerpen, - - PowerPoint PPT Presentation

UML Model Refactoring

Viktor Stojkovski

University of Antwerpen, Faculty of Computer Science, Masters of Software Engineering January, 2013, Belgium Email: Viktor.Stojkovski@student.ua.ac.be

Introduction to UML Model Refactoring

• Because of constant evolution, systems

must be modified and evolve

• There is no precise validation whether the

modifications won’t change the system behavior

• Necessity of basic set of model

transformations (refactorings)

Main goal of the project

• Create UML Statechart refactoring rules

using the defined transformations in the article Refactoring UML Models

• Define GraphGrammar rules using the

Meta-Modeling software AToM3

• Sunye, G., Pollet, D., Traon, Y. L., Jezequel, J.-M., 2001. Refactoring UML Models. Springer.
• http://atom3.cs.mcgill.ca/

Working process(1)

• 1. Reading and understanding the defined

rules and the OCL (Object Constraint Language) constraints

• 2. Create a testing model in AToM3 using

the DCharts as formalism

Group States model example

Feng, H., 2004. Dcharts, a formalism for modeling and simulation based design of reactive software systems

Working process(2)

• 3. Specify the grammar by creating the rules

– LHS and RHS

Group States rule example

Working process(3)

• 4. Add conditions to the rules as pre-

conditions and actions as post-conditions

• 5. Program the pre and post conditions in

Python

Precondition for the Fold Incoming Actions rule Acton for the FIA rule

Working process(4)

• 6. Organizing the rules in the grammar by

giving them priorities

– The order of the rules is very important (explanation!?)

Hierarchy of the rules in the GG

Working process(5)

• 7. Executing the grammar
• 8. Analyzing the results:

– Does the execution of the grammar over the statechart give the expected results? – Is the model behavior preserved?

Example of the Group State rule execution

Presentation of an example from the practical work of the project

• Refactoring a Statechart diagram that is

modeling a phone call

• Explanation of the refactoring process

through an examples

• Comparing the results of the refactoring to

the theoretical results from the article

Sunye, G., Pollet, D., Traon, Y. L., Jezequel, J.-M., 2001. Refactoring UML Models

Conclusion

• After testing the refactoring grammar on a

number of UML Statechart models the results were satisfactory

• Room for improvements:

– More wide-ranging pre and post conditions covering all of the states in which the model can be – Inventing new and expanding the already specified refactoring rules (example with the extension of the Move State out of Composite rule)

References

• Feng, H., 2004. Dcharts, a formalism for modeling and simulation

based design of reactive software systems. A Masters Thesis

• OMG, 2009. OMG Object Constraint Language (OCL). OMG
• Selic, B., 2009. Unified Modeling Language Specification (version

2.1). OMG

• Sunye, G., Pollet, D., Traon, Y. L., Jezequel, J.-M., 2001.

Refactoring UML Models. Springer

• Yang, M., Michaelson, G. J., Pooley, R. J., 2008. Formal action

semantics for a UML action language. Journal of Universal Computer Science

• http://atom3.cs.mcgill.ca/

Questions & Discussion